Thanks for the reply, I just have a small follow up.
SLComposeViewController is marked as usable in iOS 11. I understand the correct approach is to implement Twitter Kit 3, but this involves adding an SDK and creating an App on the Twitter developer portal. After a few tests I noticed that, as for Facebook sharing, it’s enough to check if the App is installed or not, (through URL Schemes), then if its installed follow the same code as now using the “SLComposeViewController”. This presents exactly the same sharing window as if using the UIActivityViewController route.
Can I assume this is a valid approach for Twitter as well? (check if the app is installed, then use the SLComposeViewController if it is, or show an alert if it isnt)
*We will probably get around implementing the Twitter Kit 3 SDK at some point though.